This invention relates to an automatic molten substance bagging system for automatically bagging a molten substance such as asphalt latex or bitumen.
Asphalt latex or bitumen is filled into paper bags in a plant and kept in custody and shipped therefrom. Such paper bags are first fed one by one into a carrying can made of a metal material with their peripheries folded inside over themselves in flattened conditions, and while held contained in the carrying cans, they are fed by a conveyor into an inflator (a bag inflating apparatus) by which they are inflated. Then, they are transported by another conveyor to a position below a filling apparatus by which they are filled with asphalt latex to a predetermined fixed weight, and then they are transported to a sealing position at which they are sealed by means of a sewing machine. After that, they are transferred onto a pallet from the carrying cans and then transported to a storage place together with the pallet by a further conveyor.
Conventionally, when asphalt latex is to be filled into a paper bag, at first a mouth of a paper bag contained in a carrying can is manually opened, and then with the mouth of the paper bag held open, the carrying can is put on a weighing instrument and asphalt latex is filled into the paper bag while measuring the weight including the carrying can.
Such an operation is dangerous (since asphalt latex is at a high temperature above 200 degrees centigrade) and requires much labor, hindering the full automation of the system. Besides, since the weight is measured continuously from an initial stage of pouring the asphalt latex until the completion of such pouring by a predetermined fixed weight, much time is required for such measurement.
Meanwhile, in an operation for feeding a paper bag into a carrying can, bags folded on themselves in flattened conditions and accumulated in a heap are separated and taken out one by one by hand and are inserted into carrying cans by hand with their bottom sides directed downwardly.
Accordingly, much time is required for such operation, having an influence on subsequent operations such as a filling operation.
Further, in a conventional dumping apparatus, as disclosed in Japanese patent publication No. 40-4878, a trippler is advanced while being rotated to tilt and move a carrying can to a position above a pallet and is then retracted while being rotated back to move back the carrying can, thereby allowing a paper bag (filled up with asphalt latex and sealed) to be pulled out of the carrying can and transferred onto the pallet.
However, because the conventional dumping apparatus transfers a paper bag while a pallet having the paper bag contained therein is held in a horizontal condition at a predetermined position, it has the following drawbacks.
In particular, when a carrying can is tilted until its opening is directed downwardly, since asphalt latex filled in a paper bag has much weight and still remains in a molten state at a high temperature, asphalt latex will flow to one side and inflate or swell an end portion (upper end portion) of the paper bag which extends outwardly from the opening of the carrying can, and due to a partial load caused thereby, the paper bag will be largely curved adjacent an edge of the opening of the carrying can and will be dropped at its inflated end portion thereof onto a horizontal pallet while it is slidably engaged with the opening edge of the carrying can. After that, upon returning upward movement of the carrying can, the paper bag is pulled out of the carrying can while being lifted by the opening edge of the carrying can. Accordingly, not only a shock upon dropping of the end portion of the paper bag is great but also the stress of lifting by the opening edge of the carrying can is high so that it may be damaged by such a great shock and a high stress additionally due to a fact that it can be readily damaged due to the heat of asphalt latex. As a result, it often occurs that asphalt latex leaks from paper bags and soils pallets and some other paper bags, resulting in the interruption of an operation.